Iphone X Weak Signal

Hi, i've a big problem with my Iphone X. In 4g reaches two bars, most of time, and this translate in bad calls and poor surfing. I've done all the appropriate procedures , including hard reset in dfu mode without result. I'm from Italy and my carrier is Vodafone. I read in a lot of forums, that modem intel a1901 has problems, does anyone confirm?